合成射流控制策略对垂直轴风力机性能影响研究

设计一种斜出口合成射流激励器并将其应用于垂直轴风力机控制其动态失速,建立不同射流孔数量的叶片并采用5种不同合成射流激励器控制策略,通过FLUENT15.0并采用Realizable k-ε湍流模型分析射流孔数量与控制策略对垂直轴风力机气动性能的影响,进一步研究垂直轴风力机涡量场结构。结果表明:当采用上开口抛物线控制策略、射流吹气系数为0.035,射流孔数量为2时,风能利用系数与平均力矩系数均提升15.2%,随着射流孔数量增多,气动性能降低;采用传统合成射流控制策略的垂直轴风力机承受近乎2倍的载荷波动,改进的控制策略可减小叶片在小攻角时的载荷波动,从而相对提升垂直轴风力机的运行稳定性;另外,合成射流技术可抑制叶片吸力面大涡的生成与发展并使叶片强尾涡削弱成多个小尾涡,减小多个叶片间的流动干扰并降低转轴尾涡强度,从而改善全局流场结构。

Effect of Flow Control Strategy of Synthetic Jet on the Performance of Vertical Axis Wind Turbine

A new beveled synthetic jet actuator had been designed and numerical investigation on the separation flow control of straight bladed vertical axis wind turbine was carried out.The aerodynamic performance of the wind turbine was comprehensively analyzed from the aerodynamic coefficients (power and torque coefficient),flow structure and vorticity field.Numerical simulation of the VAWT with different number of orifices and 5 different control strategies of synthetic jet actuator were carried out.The results show that the utilization of synthetic jet actuator with 2 orifices around trailing edge of blades and upward parabola synthetic jet control strategy at 0.035 jet momentum coefficient increases the power coefficient by 15.2%.Besides,this increment in power coefficient decreases with the increase in the number of orifices.The conventional synthetic jet actuator brings about 2 times more intense load fluctuation,but the modified one can decrease the load fluctuation.Furthermore,the trailing vortices produced by the shaft and blades interact less with each other and they are crushed into many pieces of small vortices,resulting in less strength vorticity of shedding vortices and improvement of the whole flow structure.